This invention relates to an improved yarn feed unit in a single-cylinder circular knitting machine, in particular a hose or the like knitting machine.
It is known that such yarn feed units generally comprise a number of yarn feeding fingers, e.g. five feeding fingers arranged side-by-side and independently journalled about a common axis. The yarn feeding fingers are movable independently of one another between an inoperative position, whereat their yarn guiding ends are sufficiently removed from the needle cylinder to prevent the needles from picking up the yarn, and an operative position very close to the needle cylinder, such that the needles are enabled to pick up the yarn. The yarn feeding fingers are controlled by the machine program, more specifically by the main programming drum, such as through Bowden cable controls.
The yarn feeding fingers are usually carried on a support or holder attached to a stationary portion of the machine. In this case, it is also possible to bring them all simultaneously to said inoperative position, e.g. whenever the dial is to be removed for inspection or repair, or when the machine must be reset on account of some failure. To simultaneously bring all of the yarn feeding fingers to their inoperative position, an arm is provided which is journalled to the same axis as the feeding fingers and has a small plate mounted at its bottom effective to raise all the yarn feeding fingers upon the arm itself being raised. The latter raising movement is accomplished by means of a rotatable horizontal ring which is formed at the top with a contoured profile adapted to engage a portion of said arm and either raise or lower the arm, depending on the ring direction of rotation.
The above yarn feeding units, however, still interfere with the dial raising and machine setting operations, even after the feeding fingers have been withdrawn to their inoperative position, the machine setting being an operation which involves of necessity the raising of the dial. It may happen, in fact, that the dial needles, in their protruding positions from the respective tricks, strike the yarn feeding fingers and become damaged, the needle latches being particularly prone to this trouble. Thus, a manual setting or re-insertion of the dial needles into the respective tricks must be resorted to before the dial can be raised and the setting carried out. The net result is a substantial increase of downtime and overall costs.
Also known are machines wherein the yarn feeding units are mounted on the same structure which carries the dial, thereby they can be tilted along with the dial where the latter is tilted for the aforementioned operations. This arrangement, however, also fails to prevent possible interference between the yarn feeding fingers and the dial needles, inasmuch as it does not allow all of the feeding fingers to be raised as a whole. Therefore, this known approach also requires manual setting of the dial needles, which is time consuming.